Fuse and igniter



April 3, 1951 Filed Dec. 29, 1945 G. W. HAMMAR ETAL FUSE AND IGNITER 2 Sheets-Sheet 1 'GUSTAF W. HAMMAR GEORGE A. NODDIN DONALD E. ROSEN FRANK J. TRELEASE Ap 1951 G. w. HAMMAR EI'AL 2,547,820

FUSE AND IGNITER Filed Dec. 29, 1945 2 Sheets-Sheet 2 GUSTAF w. HAMMAR GEORGE A. NOD ALD E. ROS

NK J. TRELEASE W Patented Apr. 3, 1951 OFFICE FUSE ANi) IGNITER Gustaf W. Hammar, Moscow, Idaho, George A. Noddin, Wenonah, N. J and Donald E. Rosen, Takoma Park, and Frank J. Trelease, Oxford, Md., assignors to the United States of America as represented by the Secretary of the Navy Application December 29, 1945, Serial No. 638,390

This invention relates to a, delayed action fuse which is activated by mechanical means. Further, it'relates to a delayed action fuse of the powder train type which is activated by a trigger tripping mechanism; and in particular it relates to an assembly of a delayed action fuse which is activated by a trigger tripping mechanism, which (assembly) is adapted for sub aqueous operation.

'Delayed action time fuses which depend upon the length of the powder train for their timing function and mechanically tripped triggers which detonate primers are both known. But in general these are not adapted to function under water nor to operate efiiciently under the severe conditions which this invention eificiently meets. This invention functions under certain conditions of time, interior pressure, external pressure, temperature and under water.

,It is, therefore, the general object of this invention to provide apparatus adaptedto function under the above stated conditions and more specifically; V V It is an object of this invention to provide a mechanically activatedfuse for such apparatus the igniting action of which is delayed from 5 to 6 seconds. i lt is also an object of this invention to provide an assembly of a mechanically activated fuse therefor, the structure of which will withstand an external pressure of 200 lbs. per square inch and an internal pressure of 1000 lbs. per square inch. V

It is a further object of the invention to provide an assembly of a mechanically activated fuse the structure of which is capable of withstanding a gas at high temperature in contact with its inner surfaces while itsouter surfaces are'in contact with water at meteorological temperatures. "It is still a further object of this invention to provide a mechanically activated fuse which is 3 Claims. (01. 102 -7) the trigger tripping mechanism of the apparatus of the present invention, partly in elevation, taken along section line I| of Figure 2 in the direction indicated by the arrows;

Figure 2 is a vertical longitudinal section through the trigger tripping mechanism and associated structure, partly in elevation, taken along line 22 of Figure 1 in the direction indicatedby the arrows;

Figure 3 is a vertical longitudinal section through the delayed action fuse, partly in elevation, taken along line 33 of Figure 5 in the direction indicated by the arrows;

ignite trench mortar sheet powder at a distance of two inches at low temperatures.

Referring further to the drawings, the same numerals are used throughout the different figures to represent the same elements wherever applicable. In Figure 2, l0 represents generally the assembly of a trigger, trigger tripper, delayed action cartridge fuse and supporting structure. The latter comprises end plates l2 and [4 which are spaced apart by posts l6, I8, 20 and 22. End plate I2 is threaded as at l3 for engagement with a tubular member such as gas-receiving tube 64. End plate I4 is bored centrally as at I5 to receive fuse cartridge I! by threaded engagement as at [9. Post It is slotted as at 2| to receive and pivotally support trigger 24 and tripper 26 at 23 and 25 respectively. Trigger 24 is biased toward end plate l4 by coiled spring 28 which is capable'of igniting in an enclosed space black powder at a distance of three "inches and trench mortar sheet powder at a distance of one inch. It is an additional object of the invention to provide an assembly 'of a mechanically activated fuse structurew'hich is sufiiciently strong and durable to meet the above objectives, but which isrelatively light in weight and capable of chicient manufacture.

With these objectives in viewre ference is now made to'the drawings which are illustrative of a preferredembodiment of the invention, and in Figure 1 is a vertical transverse section through carried on pin 30 and held in biasing position by pin 32. Trigger 24 is provided with firing pin 34 which enters port 21 when trigger 24 is released by tripper 26. The latter is provided with adetent 29 which engages the free end of trigger'24. When the tripper is rotated a suificient distance toward end plate I2. trigger 24 is released from engagement with detent '29 and spring 28 drives firing pin 34 through port 21 with force sufficient to detonate the primer in fuse cartridge l1. Tripper 26 is held in safety position by'pin 36 which is biased toward unlocked position by spring 38. Pin 36 and spring 38 are held in locked position by cotter pin 40 to which is freely attached ring 42. Pin 36, spring 38 and cotterpin 40 are housed or supported by bushing 44 which threadedly engages post 20 as 7 3 at 45 in alignment with channel 46. Bushing 44 is provided with a closure washer 41 which limits the throw of pin 36. Upon the withdrawal of cotter pin 40 from bushing 44 pin 36 is released from looking position by spring 38 and trigger 24 and trigger 26 are in firing position, i. e. tripper 2B is free to swing trigger 24 toward plate l2. Tripper 26 is actuated by tripper bar 48 which is longitudinally positioned exteriorly of post 20 and tube 64 and is supported by flat head screws 54 which extend through elongated slots the trip per bar and into threaded engagement with tube 64 as shown in Figure 1. The end of the tripper bar 48 toward plate i4 is off set as at 51 and is supported by bifurcated retaining plate 52 which is held in position by countersunk screw 53 which is threaded into engagement with end plate I4. This end of tripper bar 48 is slotted as at 61 to fit freely around the projecting end 50 of tripper 26. The other end of tripper bar is provided with a hook 55 of adequate stiffness to sustain a pull great enough to actuate the tripper but not so stiff that it does not bend out or the way when the ram pushes the device through the launching tube past the abutment on which hook 55 of the tripper bar impinges. Gas ducts 56 and 58 extend through end plates l2 and I4 and spacing posts it and 22 respectively, thereby providing egress for the apparatus gases generated by the combustion of material such as various types of powder, fuel etc. which prefer ably may be contained in fuel ignition chamber such as defined by fuel tube 66 as shown in Fig:

ure 2, and which threadedly engages end plate 14 as at 62. These apparatus gases passing through ducts 5B and 58 enter gas-receiving chamber 64 which is adapted to threadedly engage end plate 12 as at 65. The use of these apparatus gases forms no part of this invention, but they are used for different functions in the various types of devices launched from submarines. i v

Fuse cartridge l'i, for reasons of economy, consists of two types; one is adapted to ignite black powder under the vconditions stated above and the other is adapted to ignite trench mortar sheet powder under the conditions stated. This other type would ignite the black powder too, but it employs alarger volume of igniter mixture 7 and hence is not used forthis purpose.

Figuresfi, 4. and 5 illustrate the first type of delayed action fuse. t consists of a cylindrical metallic body 17 comprising head portion 12, neck portion 34 and main body portion 16. The main body portion it is threaded as at 18 to engage end plate it as at [9. The cartridge is bored axially as at H to a shoulder 13 in neck 14. The bore is continued at a reduced diameter as at and flares out into a cavity T! in head i2. Body portion 76 is cut away asat 89 to provide opposite faces for the application of a wrench by means .of which the cartridge is screwed home sufilciently in combination with copper cups 82 to form a gas tight seal. Body portion '15 isalso chamfered as at 84- to stream'-. line and to reduce the weight of the body. In the; neck portion '14 a gasvent 86 isprovided for the escape of gases developed when the primer is detonated.

The loading of this type of fuse cartridgecomprises a percussion primer 88 of any well known type, a copper cup gasket 82, a column of gasless delay powder 92 consisting of 8l--85% of barium peroxide and 19-45% of selenium towhich may or may not befladded .0-3% of- French chalk 4 (talc), and an increment of 90-10 meal powdermagnesium as the igniter 94. The gasless delay powder is rammed and packed in the bore of the cartridge under a pressure of 8200 p. s. i. The igniter mixture is packed under a pressure of 41-00 p. s. i-. This loading is capable of ignit-' ing black powder over an air gap of twenty one inches in open air. The average delay time i. e. from the detonation of the primer to the spitting of the igniter mixture is 5.7 seconds.

The loading of the type of cartridge disclosed by Figure 6 is similar to that above except that volume of igniter mixture is enlarged by increasing the diameter and the depth and the proportion of black powder to magnesium is changed to 75-25. Maintaining the length of the column of gasless delay powder the same necessitates increasing the overall length of the cartridge by the amount of the increase in the depth of the igniter mixture. This loading ignites the trench mortar sheet powder at a distance of two inches in 5.7 seconds.

' The preferred: embodiment of the two types of fuses herein defined functions satisfactorily under the. severe conditions set forth in the objectives, supra; It functions efliciently under water with the extreme temperature difference existing, between that of the ignition gases pass-"- ing through the ductsfrom the igniter chamber and to the operating chamber and that of the surrounding water. The device also. functions under the objective conditions of internal and external pressure.

While the above specification has been drawn to a preferred embodiment of the invention it is not desired to be strictly limited thereto as other types of trigger tripping mechanism-,- other types of cartridges and loading and other housing structure could obviously be used. Sueh other types are within the spirit and scope or this invention to theextent as defined by the herewith appended claims;

What is claimed is:

'1; In combination, tua-ted apparatus: afirst tube defining agas receiving chamber, a second tube defining afuel igniting chamber; and a fuse assembly connect: ing said chambers in cooperating relationship; saidassemblycomp'rising: an axially bored me; tallic fuse cartridge; a percussion primer; trigger arranged to' detonate saidprimerj' 'a tripper arranged to release said trigger; a trip bar arranged to actuate said tiip'per; said bar being mounted for longitudinal sliding one g'agem'ent along the outer surface of one of said tubes; circular end plates engaging said tubes: a pair of aligned gasducts in' each of said plates; said plates" being s aced apart" by four posts positioned circumferentially at intervals of ninety degrees; one of said posts being adapted to pivotally support said trigger and said tripper'; the

sealing cup, and includes a rammed train-of gasless delay powder consisting. 81 to 85%- ba riumperoxide, 15 to 19%. selenium and a ramx ndignition mixture; consisting of ninety partsmeal powder and-- ten parts-magnesium.

in under water fuse to-- 3. An under water fuse-assembly adapted to inter-connect a pair of longitudinally aligned tubes; said assembly comprising: an axially bored metallic fuse cartridge; a percussion primer; a trigger arranged to detonate said primer; a tripper arranged to release said trigger; a trip bar arranged to actuate said tripper; said bar being adapted to be mounted for longitudinal sliding engagement along the outer surface of one of said tubes; circular end plates engaging said tubes; a pair of aligned gas ducts in each of said plates; said plates being spaced apart by four posts positioned circumferentially at intervals of ninety degrees; one of said posts being adapted to pivotally support said trigger and said tripper; the opposite of said posts being adapted to guide the free end of said tripper into cooperating engagement with said bar; each of the other of said posts having gas ducts therein in respective aligmnent with said ducts in said plates.

G.- W. ,HAMMAR. G. A. NODDIN. D. E. ROSEN. F. J. TRELEASE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,307,684 Leblanc June 24, 1919 1,815,226 Anderson July 21, 1931 1,999,820 Nash Apr. 30, 1935 2,000,617 Schaffler-Glossel May 7, 1935 2,075,813 King Apr. 6, 1937 2,079,178 Mortreux May 4, 1937 2,139,581 Hanley Dec. 6, 1938 

